fix: 适配 ubuntu 路径并增强换发色/训练流程稳定性

将配置与训练脚本从 /home/xsl 切到本机 /home/ubuntu；换发色在 webui 增强失败或缺色板时降级返回，训练结束后自动重启 hair 服务再回调。

Co-authored-by: Cursor <cursoragent@cursor.com>

train_hairstyle_full.py

@@ -158,6 +158,10 @@ def step3_wait_and_callback(hair_id, template_img):
     else:
         print("  ✗ 训练超时"); return False
     time.sleep(5)  # 等训练进程写完
+    # 训练时停掉了 hair 服务，回调前需要重启
+    print("  重启 change_hair-hair 服务...")
+    os.system("sudo systemctl restart change_hair-hair")
+    time.sleep(20)
     # 触发回调生成ref材质
     print("  触发回调生成ref材质...")
     r = req.post(HAIR_CALLBACK, json={"task_id":f"train_{hair_id}","hair_id":hair_id,